Snowmobile fuel pump problems can be diagnosed. A vacuum fuel pump is used on snowmobiles with carburetors. The first thing to look at is the vacuum line that will run to the crankcase. If this hose has any cracks, leaks or is not clamped tightly on to the crankcase fitting, it will not pump fuel. If the fuel pump still wont work, mark where the lines come from and make a line down the side of the pump. Disassemble the pump carefully and look at the diaphragms for cracks. Also inspect for blockage of any of the cavities or passages within the fuel pump. You can also spin the engine over to make sure the crankcase fitting is not blocked. This fitting will produce vacuum and pressure so don’t be alarmed. If you can’t find any problems rebuild or replace the pump. Fuel injected snowmobiles will use an electric fuel pump. First check to see that there is voltage coming to the fuel pump.
Also check the ground wire. If not, check the solenoid, to make sure it’s signal wire (small positive wire)is causing the power to cross the solenoid (two large wires). Also check for any fuses that are inline with the positive wire. Next turn the snowmobile to the off position and look for the valve to check fuel pressure or remove the hose and point it into a container. Turn the key to the run position. If fuel is spraying out then the fuel pump is working. If no fuel is coming out or very little then check the fuel filter or look for any pinched hoses. If nothing else seems to be wrong then replace the fuel pump.